Isolate the unit, open the chassis, and check the seating of all ribbon cables and push-on connectors. Symptom: Excessive Noise or Vibration
Inspect the fan blade for physical play. Replace the fan assembly if the bearing noise persists after cleaning. Tighten all exterior casing screws. 5. Storage and Decommissioning
If the unit is removed for storage, the battery must be maintained according to specific outgassing and temperature protocols to prevent degradation. Where to Source These Documents You can obtain official copies from these sources:
Turn off the unit, disconnect all cables, and place it on an ESD-safe mat. ps-855b maintenance manual
: A brief functional test recommended before each flight to ensure the unit is operational. Capacitance Testing
Check all external cable connections for frayed shielding or bent pins.
Procedures (like those in SL-170) for troubleshooting. Isolate the unit, open the chassis, and check
The maintenance manual is filled with specific technical data that technicians must reference for tasks like bench testing and troubleshooting. The following table summarizes the key specifications for the PS-855B.
For deeper diagnostics, the L3Harris PS-855B maintenance manual may reference the "ShockBox BFG Capacitance Test Box" (Part #: SB24-03-835). This manually operated test unit is designed specifically for the PS-835, PS-850, and PS-855 series. It allows a technician to apply a precise load to the battery and verify its capacity against the parameters in the manual.
Essential for initial setup and verifying the unit's interface with the aircraft's electrical system. Key Maintenance Requirements Tighten all exterior casing screws
Fan failure; blocked air vents; excessive ambient room temperature.
Locate and remove the four captive retention screws on the perimeter of the top access panel.
[PS-855B Power Supply] ---> [Digital Multimeter (DMM)] (Output Terminals) (DC Voltage Mode) Voltage Meter Calibration
Remove the top cover shroud. Use dry, low-pressure compressed air to blow away accumulated dust from the main PCB board, power transformer, and heatsinks.
The difference between a power supply that gets scrapped and one that runs for another decade is often a single page in a . Whether you are a field service engineer, a hobbyist restoring industrial gear, or an in-house maintenance tech, the manual gives you the schematic truth—no guesswork, no myths.